Wireless Charging System for Electric Vehicle

This application claims priority to Korean Patent Application No. 10-2024-0177751 filed on Dec. 3, 2024, the entire contents of which are herein incorporated by reference.

The present disclosure relates to a wireless charging system for an electric vehicle, which implements a low cost and high efficiency by accurately aligning a receiver coil and a transmitter coil horizontally and vertically before the start of charging in a way to induce the parking of an electric vehicle so that a transmitter pad and a receiver pad are horizontally aligned through communication with an inverter and the recognition of a parking line by calculating a relative location of the transmitter pad to the receiver pad in real time when the electric vehicle enters a parking area for charging and adjusting the height of the transmitter coil by using height adjustment means provided on the transmitter pad after parking.

Contents described in this part merely provide background information of the present embodiment and do not constitute a conventional technology.

A charging method of an electric vehicle charger is divided into a wired charging method of performing charging by directly connecting a plug to a vehicle and a wireless charging method of performing charging in a contactless manner by using a self-induced method without a plug.

A common wireless charging system for an electric vehicle has a structure in which a battery is charged by transmitting power between a transmitter pad installed at the floor of a parking lot and a receiver pad mounted at the bottom of an electric vehicle through self-induction, and may include an inverter that inputs a high-frequency current to the transmitter pad and a rectifier circuit that inputs a charging current to the battery by rectifying the output of the receiver pad.

A wired charger has good charging efficiency, but has inconvenience in that a heavy and complicated plug needs to be put in and pulled out from a vehicle whenever charging is performed. In contrast, a wireless charger has an advantage in that charging is very convenient because a vehicle is automatically charging as long as the vehicle is parked. However, the wireless charger has problems in that it is difficult to accurately horizontally align a transmitter pad and a receiver pad depending on a parking location of a driver and vertical alignment is not easy because the ground height (i.e., the height of a bottom surface) of a vehicle is different depending on the type of vehicle. A current wireless charging technology needs to permit a predetermined range of a horizontal alignment error and needs to be designed to have a wide air gap range due to such problems. Current international standards require an error tolerance of ±7.5 cm in forward and backward directions of a vehicle and ±10 cm in the horizontal direction of the vehicle. There is a problem in that an air gap change of the lowest ground height, that is, about 12 cm, to 30 cm in the vertical direction needs to be accommodated. In this case, there are disadvantages in that the size of the transmitter pad is much greater than the size of the receiver pad charger efficiency is very low.

Furthermore, from the nature of the charging of a self-induced method, a metal foreign object detection (FOD) function is required because there is a danger of fire when a metallic object is present between the transmitter pad and the receiver pad. A live object detection (LOD) function is essentially required because if a creature, such as a dog or a cat, approaches the transmitter pad during charging, such an approach may affect the human body. Moreover, a position detection (PD) function for determining whether the receiver pad of an electric vehicle has been aligned with the transmitter pad is also required.

However, the current FOD, LOD, and PD techniques have disadvantages in that a cost is high and lots of errors occur because a complex hardware construction and a software algorithm are required.

In addition to such high cost and low efficiency (about a difference of 5% compared to wired charging) problems, there is a problem in that the capacity of a charger cannot be much increased due to a problem with a rise in costs. Today, only a slow charger of about 11 kW has been developed, and has not yet been commercialized due to high costs. An 11-kW wireless charger will be suitable for overnight charging for home use, but has a problem in that the 11 kW wireless charger is not sufficient in the field in which charging is frequently performed and a case in which a person has to get back to work quickly after charging, like a robot taxi.

A robot taxi requires quick charging of at least 50 kW or more, and has a problem in that it is not easy to overcome a high cost price and a low efficiency problem.

Recently, in order to maximize efficiency of power transmission between the transmitter pad and the receiver pad, there is suggested a method of horizontally aligning the transmitter pad and the receiver pad by using an automatic parking function for an electric vehicle and constantly maintaining an air gap with respect to the receiver pad regardless of the ground height of the electric vehicle by adjusting the height of a transmitter coil through a height adjustment device added within the transmitter pad. This method has advantages in that the size of the transmitter pad can be significantly reduced and efficiency can be maximized when horizontal alignment and vertical alignment are well performed. However, a current automatic parking technology has difficulty in implementing accurate horizontal alignment between the transmitter pad and the receiver pad because the current automatic parking technology is merely at the level at which a vehicle is simply aligned at the center of a parking area. The reason for this is that the size of an electric vehicle is different depending on the type of electric vehicle, a location at which the receiver pad is installed is different, and the size of a parking area or a location at which the transmitter pad is installed has not been standardized.

Accordingly, in order to properly commercialize a wireless charger, there is a need to develop a new wireless charging technology capable of securing both economics and high efficiency while supporting the conventional functions without any change.

Various embodiments are directed to improving the accuracy of horizontal alignment compared to a conventional technology by calculating a relative location of a transmitter pad to a receiver pad in real time through a parking line recognition function and communication with an inverter and using the relative location in the horizontal alignment when an electric vehicle enters a parking area for charging.

Furthermore, various embodiments are directed to reducing the size of the transmitter pad and maximizing power transmission efficiency by improving the structure of alignment means for vertical alignment and also minimizing a cost price for the entire system by separately implementing the FOD, LOD, and PD functions.

In an embodiment, a wireless charging system for an electric vehicle includes a parking area in which a parking line is indicated, a transmitter pad installed in the parking area, an inverter configured to supply AC power to the transmitter pad and having a communication function, an electric vehicle having a parking line recognition function and a communication function using a camera, a receiver pad attached to a bottom surface of the electric vehicle, and a wireless charging platform.

The electric vehicle memorizes a location at which the receiver pad is attached within the electric vehicle. The inverter memorizes the location of the transmitter pad on the basis of the parking line in the parking area.

When the electric vehicle enters the parking area for charging, the electric vehicle recognizes a horizontal alignment state between the receiver pad and the transmitter pad by calculating a relative location of the transmitter pad to the receiver pad in real time by recognizing the parking line using the camera while communicating with the inverter. In this case, communication pairing between the electric vehicle that enters the parking area and the inverter may be performed as the inverter recognizes the number of the electric vehicle through a camera included therein and selects a communication ID connected to the number of the electric vehicle.

Furthermore, in an embodiment of the present disclosure, the electric vehicle includes a monitor, displays the fixed location of the receiver pad on the monitor upon parking, calculates the relative location of the transmitter pad to the receiver pad, and displays results of the calculation on the monitor so that a driver is induced to park the electric vehicle so that the transmitter pad and the receiver pad are horizontally aligned while viewing the monitor.

Furthermore, the electric vehicle includes an automatic parking function, performs automatic parking by recognizing a location of the parking line upon parking, and performs the automatic parking so that the transmitter pad and the receiver pad are horizontally aligned by calculating the relative location of the transmitter pad to the receiver pad attached to the electric vehicle.

Furthermore, in an embodiment of the present disclosure, the transmitter pad includes a transmitter coil capable of a vertical movement thereon. Vertical alignment with the receiver pad is performed by adjusting the height of the transmitter coil.

Furthermore, the inverter includes a camera and a lighting device or a thermal imaging camera that are disposed outside the parking area and are directed toward the transmitter pad, and inspects whether a metallic foreign substance is present on the transmitter pad when an electric vehicle is not present in the parking area or while an electric vehicle is charged.

Furthermore, the transmitter pad includes one or more second thermal imaging cameras or second cameras and second lighting devices that protrude from a surface of the transmitter coil within a predetermined distance or less outside the transmitter coil, and inspects whether a heating point attributable to a metallic foreign substance or an external creature is present between the transmitter pad and the receiver pad in real time while the electric vehicle is charged.

The wireless charging system for an electric vehicle according to an embodiment of the present disclosure is constructed to enable an electric vehicle to be parked so that the transmitter pad and the receiver pad are horizontally aligned by calculating a relative location of the transmitter pad to the receiver pad in real time through communication the inverter and the recognition of a parking line when the electric vehicle enters a parking area for charging, and to start charging after vertical alignment with the receiver pad is achieved by adjusting the height of the transmitter coil through the transmitter pad including the transmitter coil capable of being vertically moved on the transmitter pad after the parking is completed. By such a construction, the structure of the transmitter pad can be simplified, and the size of the transmitter pad can be minimized, and power transmission efficiency can be maximized. Furthermore, there is an advantage in that a cost price for a wireless charger can be efficiently reduced because functions, such as the FOD, LOD, and PD functions, are separated from the inside of the transmitter pad and placed outside. Accordingly, the wireless charging system according to an embodiment of the present disclosure can extend a wireless charging capacity that is conventionally merely at a 1 kW level up to a 50 to 300 kW and can achieve high power transmission efficiency of about 93 to 95% which is close to power transmission efficiency of a wired charger.

Embodiments of the present disclosure will be described in detail as follows with reference to the accompanying drawings. The following detailed description is merely exemplary and merely illustrates some embodiments of the present disclosure.

1 FIG. 1 FIG. is a configuration diagram of a conventional wireless charging system for an electric vehicle.illustrates the structure of a wireless charging system for an electric vehicle when a transmitter pad is implemented in a form in which the transmitter pad is fixed to the floor of a parking area. Hereinafter, during the course of describing the wireless charging system for an electric vehicle, for clear distinction, in some drawings, the main body of the electric vehicle is omitted, and only a receiver pad is illustrated and described. Furthermore, in the case of the transmitter pad and the receiver pad, a transmitter coil and a receiver coil included in the transmitter pad and the receiver pad, respectively, are omitted, and only appearances of the transmitter pad and the receiver pad are illustrated and described.

1 FIG. 100 102 110 100 112 120 122 130 110 132 130 110 Referring to, the wireless charging system for an electric vehicle may basically include at least one electric vehicle wireless charger, including a parking areathat is install within a parking space and in which a parking lineis indicated, a transmitter padthat is installed at the floor of the parking areaand that includes a transmitter coilon the transmitter pad, a receiver padthat is installed under an electric vehicle and that includes a receiver coilthat collects power through magnetic coupling with the transmitter coil, an inverterthat is connected to the transmitter padand that provides charging power, and a charging cablethat electrically connects the inverterand the transmitter pad.

110 130 110 132 130 110 132 130 110 In this case, the transmitter padmay be installed on the parking area or a part of or the entire transmitter pad may be buried and fixed to the parking area. The inverteris disposed by being isolated from the transmitter pad. The charging cableelectrically connects the inverterand the transmitter pad. The charging cablemay be buried in the ground or may be disposed on the ground through a cable duct, and may transmit charging power supplied from the inverterto the electric vehicle through the transmitter pad.

120 110 120 110 110 120 110 120 In the wireless charging of the electric vehicle, a method of disposing the electric vehicle on which the receiver padis mounted on the transmitter padinstalled on the ground, inducing power into the receiver padof the electric vehicle by using magnetic induction power that is generated by applying a current to the transmitter padso that a battery included in the electric vehicle is charged is used. In general, power transmission efficiency of such a wireless charging system is determined by the alignment degree of the transmitter padand the receiver padand a distance between the transmitter padand the receiver pad, that is, an air gap.

However, a fixed type transmitter pad method has limitations in that it is difficult to accurately align the transmitter pad and the receiver pad depending on a parking method of an electric vehicle. A driver may attempt to align the transmitter pad and the receiver pad with reference to parking area information displayed on a monitor in an electric vehicle, but practically has difficulty in precisely aligning the transmitter pad and the receiver pad. Accordingly, in the international standards, a horizontal alignment tolerance is regulated as ±7.5 cm in forward and backward directions and ±10 cm in the horizontal direction. Furthermore, the air gap between the transmitter coil and the receiver coil is variously changed from about 12 cm to 35 cm depending on the ground height of an electric vehicle. In order to compensate for such an alignment tolerance, in general, the size of the transmitter pad needs to be designed about two times or more that is greater than the size of the receiver pad. Even though, the reality is that wireless charger efficiency is maximized of about 90%, which is about 5% lower than charger efficiency of a wired charger.

Furthermore, a foreign object detection (FOD) function for detecting a metallic foreign substance is essentially required because induction heating may occur and result in a fire due to a metallic foreign substance when the metallic foreign substance is present between the transmitter pad and the receiver pad. Furthermore, a live object detection (LOD) function is also required because an animal, such as a dog or a cat, may be hazardous if the animal is present on or around the transmitter pad. Furthermore, there is a need for a position detection (PD) function for recognizing an alignment state between the transmitter pad and the receiver pad. In order to implement these functions, separate auxiliary coils and complex sensing circuits are necessary for the transmitter pad and the receiver pad. For these reasons, the existing wireless charging system has an obstacle to commercialization because the existing wireless charging system has disadvantages, such as a high cost price, low efficiency, and a large pad size, and experiences the frequent occurrence of a charging obstacle problem attributable to erroneous detection because the level of completion of the FOD and LOD technologies is low.

2 FIG. 2 FIG. 112 122 112 110 110 120 110 120 112 110 110 110 120 120 110 120 110 is a diagram for describing a wireless charging system for an electric vehicle according to another conventional embodiment.exemplifies a wireless charging structure for an electric vehicle, which has been implemented to constantly maintain an air gap between the transmitter coiland the receiver coilby adjusting the height of the transmitter coilwithin the transmitter pad. Such a method is a method of constantly maintaining the air gap between the transmitter padand the receiver padby horizontally the transmitter padand the receiver padby using the automatic parking function of an electric vehicle and adjusting the height of the transmitter coilregardless of the ground height of the electric vehicle through a height adjustment device added within the transmitter pad. The method has advantages in that both horizontal alignment and vertical alignment can be accurately performed, the size of the transmitter padcan be significantly reduced, and power transmission efficiency can be maximized. However, a current automatic parking technology has limitations in that it is difficult to implement precise horizontal alignment between the transmitter padand the receiver padbecause the current automatic parking technology is merely at the level at which an electric vehicle is simply aligned at the center of a parking area. The reason for this is that the size of an electric vehicle and the location at which the receiver padis attached within an electric vehicle are different for each electric vehicle and the size of a parking area or the location at which the transmitter padis installed within the parking area also has not been standardized. Accordingly, in order to realize accurate horizontal alignment, it is necessary to standardize the location at which the receiver padis attached within an electric vehicle and the location at which the transmitter pad is installed for each electric vehicle manufacturer, but this is practically difficult because interests between the manufacturers are different. As a result, if only vertical alignment is performed in the state in which horizontal alignment has not been properly performed. It is difficult to obtain high efficiency. Furthermore, there is still a cost price rise problem because the FOD and LOD functions are required within the transmitter padas in the existing technology.

Accordingly, embodiments of the present disclosure propose a wireless charging system for an electric vehicle using a new alignment method, which has both economics and high efficiency by improving the problems of the conventional wireless charging system for an electric vehicle.

3 FIG. 3 FIG. 110 120 110 120 110 120 illustrates a preferred alignment state between the transmitter pad and the receiver pad in a wireless charging system for an electric vehicle. As illustrated in, if both horizontal alignment and vertical alignment between the transmitter padand the receiver padare accurately performed, the sizes of the transmitter pad and the receiver pad can be minimized and high efficiency can be obtained at a low cost price because the air gap can be minimized. However, the transmitter padhas to be moved or the receiver padhas to be moved for horizontal alignment because the transmitter padis installed in a parking area and the receiver padis attached to the bottom of an electric vehicle. An embodiment of the present disclosure proposes the latter method, that is, a method of moving the receiver pad, that is, a method of performing horizontal alignment by moving the electric vehicle.

4 FIG. is a diagram for describing a construction and operation of a wireless charging system for an electric vehicle according to an embodiment of the present disclosure.

200 202 210 200 212 220 240 222 212 230 210 232 230 210 The wireless charging system for an electric vehicle according to an embodiment of the present disclosure may basically include at least one electric vehicle wireless charger, including a parking areain which a parking lineis indicated, a transmitter padthat is installed in the parking areaand that includes a transmitter coilon the transmitter pad, a receiver padthat is installed at the bottom of an electric vehicleand that includes a receiver coilthat receives power through magnetic coupling with the transmitter coil, an inverterthat is connected to the transmitter padand that provides charging power, and a charging cablethat electrically connects the inverterand the transmitter pad, as in a conventional wireless charging system for an electric vehicle. Hereinafter, for convenience' sake, one electric vehicle wireless charger is described as an example, but one or more electric vehicle wireless chargers may be included in an actual wireless charging system for an electric vehicle.

Furthermore, the wireless charging system for an electric vehicle according to an embodiment of the present disclosure may further include a wireless charging platform (not illustrated) that is responsible for control of the entire charging system, if necessary.

210 210 The wireless charging system for an electric vehicle according to an embodiment of the present disclosure has improved a structure for vertical alignment while increasing the accuracy of horizontal alignment compared to a conventional system in a method of aligning the transmitter coil and the receiver coil. Furthermore, the wireless charging system has advantages in that the size of the transmitter padcan be minimized, a structure can be simplified, and power transmission efficiency can be maximized because some functions, such as the FOD and LOD functions, are separately implemented outside the transmitter pad.

210 220 202 230 240 200 220 210 212 222 210 An alignment method for electric vehicle wireless charging according to an embodiment of the present disclosure includes calculating a relative location of the transmitter padto the receiver padin real time through the recognition of the parking lineand communication with the inverterwhen the electric vehicleenters the parking areafor charging. Accordingly, the electric vehicle can be parked so that the transmitter pad and the receiver pad are horizontally aligned based on the recognized horizontal alignment state between the receiver padand the transmitter pad. After the horizontal alignment is completed, vertical alignment that constantly maintains the air gap between the transmitter coiland the receiver coilby adjusting the height of the transmitter coil by using height adjustment means included in the transmitter padmay be performed.

Hereinafter, horizontal alignment and vertical alignment methods according to an embodiment of the present disclosure are described more specifically.

240 220 220 242 202 First, the horizontal alignment method is described. In an embodiment of the present disclosure, the electric vehiclemay memorize the location of the receiver padattached within the electric vehicle, and may calculate the relative location of the receiver padon the basis of a reference object that is present at a predetermined location on the parking area recognized by a camerainstalled in the electric vehicle. The reference object may be the parking linethat partitions the parking area. Hereinafter, the parking line is described as an example of the reference object, but the present disclosure is not limited thereto.

230 202 210 200 202 Furthermore, the inverterdisposed outside the parking lineincludes a camera and a communication function, and memorizes the relative location of the transmitter padinstalled in the parking areato the parking line.

4 FIG. 240 200 240 210 230 Accordingly, as illustrated in, when the electric vehicleenters the parking areafor charging, the electric vehiclerecognizes front and side parking lines through a parking line recognition function, and also collects information on the relative location of the transmitter padto the front and side parking lines through communication with the inverter.

230 200 230 240 The inverterrecognizes the number of the electric vehicle that is entering the parking areaby using the camera of the inverter during a process of communicating with the electric vehicle, searches for a communication ID that is connected to the number of the electric vehicle, and performs pairing between the inverter and the electric vehicle. Accordingly, the inverterand the electric vehiclecan communicate with each other in real time, and a Wi-Fi method may be used for the communication.

240 230 230 Furthermore, the wireless charging platform may collect and share basic information related to charging by performing communication between the electric vehicleand a smartphone of a user or the inverterbefore the start of the charging. In this case, the basic information related to charging may include the type of electric vehicle, the number of the electric vehicle, electric vehicle information, such as pairing information for a communication connection with the electric vehicle, charging information, such as the amount of charging, a charging fee, a charging time, and a charging voltage, and user information, such as a user name, payment means, and user input information. The inverteridentifies charging intention through communication with the electric vehicle, and starts a charging processor when the charging intention is identified.

230 240 210 In another embodiment, the wireless charging platform may memorize the relative location of the transmitter pad to the parking line instead of the inverter. In this case, the electric vehiclemay collect relative location information on the transmitter padthrough communication with the wireless charging platform.

240 210 220 210 230 240 300 210 220 The electric vehiclememorizes the location at which the receiver pad is attached within the electric vehicle, and recognizes the horizontal alignment state between the transmitter pad and the receiver pad by calculating the relative location of the transmitter padto the receiver padin real time based on parking line recognition information and location information of the transmitter padthat is collected from the inverter. The electric vehicleaccording to an embodiment of the present disclosure may display the recognized horizontal alignment state on a monitorwithin the electric vehicle, and may perform parking so that the transmitter padand the receiver padare horizontally aligned by using the recognized horizontal alignment state.

240 234 230 240 230 230 210 220 However, the parking line recognition function of the electric vehiclemay not be precise. In order to supplement such a problem, the cameraof the invertermay sense the left and right alignment state of the electric vehiclethat enters the parking area, and may support that the electric vehicle can be aligned more accurately through communication. The camera is disposed at an upper part of the inverter, and may determine the left and right alignment state of the entire electric vehicle. In another embodiment, the camera may be disposed at a lower part of the inverter, and may directly determine the left and right alignment state between the transmitter padand the receiver pad.

5 FIG. 240 300 220 210 300 is a diagram illustrating a process of aligning the transmitter pad and the receiver pad, which is displayed on the monitor in the electric vehicle upon parking, according to an embodiment of the present disclosure. The electric vehicleaccording to an embodiment of the present disclosure includes a monitor, and displays a relative location between the receiver padand the transmitter pad, which is calculated in real time, on the monitorin order to induce a driver to park the electric vehicle so that the transmitter pad and the receiver pad are horizontally aligned.

240 220 210 220 300 210 210 210 220 300 210 220 300 5 FIG. More specifically, the electric vehicledisplays the relative location between the receiver padand the transmitter padon the basis of the location of the receiver padfixed on the monitor, and may display a change in the location of the transmitter padin real time by incorporating the relative location of the transmitter padthat is calculated in real time. Referring to, the relative location of the transmitter padto the receiver pad, which is changed as the electric vehicle moves, is calculated in real time. The results of the calculation are incorporated and displayed on the monitor. Accordingly, a driver can accurately park the electric vehicle so that the transmitter padand the receiver padare horizontally aligned while viewing the monitor.

240 220 210 240 210 220 In addition to manual parking, the electric vehiclehaving an automatic parking function may operate the automatic parking function so that the receiver padand the transmitter padare horizontally aligned. That is, the electric vehicleincludes the automatic parking function, performs automatic parking by recognizing the location of a parking line upon parking, but may perform automatic parking so that the transmitter pad and the receiver pad are horizontally aligned by calculating the relative location of the transmitter padto the receiver padthat is attached to the electric vehicle.

200 210 210 210 220 240 Rear parking may be required and head-on parking may be possible, depending on the structure or space of the parking area. In the wireless charging system according to an embodiment of the present disclosure, the location at which the transmitter padis installed may be different because a rear parking area and a head-on parking area are divided. In general, it is preferred that the transmitter padis installed at a front part of a parking area upon head-on parking and the transmitter padis installed on the entrance side of a parking area upon rear parking because the receiver padis attached near the front wheel of an electric vehicle. The wireless charging platform may lead the electric vehicleso that head-on parking or rear parking is performed depending on a condition for each parking area for smooth wireless charging.

6 FIG. 210 203 240 210 202 230 is a diagram illustrating an overall process in which the transmitter pad installed in a head-on parking-dedicated parking area and the receiver pad are horizontally aligned in the wireless charging system for an electric vehicle according to an embodiment of the present disclosure. In order for the electric vehicle to be accurately parked at the center of the parking area, it is preferred that the location of the transmitter padis disposed near a stopper. In this case, the electric vehiclemay receive information on the relative location of the transmitter padto the parking linethrough communication with the inverterwhile forward entering the parking area, and may perform parking so that the transmitter pad and the receiver pad are horizontally aligned based on the received information.

7 FIG. 210 210 230 is a diagram illustrating an overall process in which the transmitter pad installed in a rear parking-dedicated parking area and the receiver pad are horizontally aligned in the wireless charging system according to an embodiment of the present disclosure. In this case, it is preferred that the transmitter padis disposed on the entrance side of the parking area. The electric vehicle may receive information on the relative location of the transmitter padto the parking line through communication with the inverterwhile backward entering the parking area, and may perform parking so that the transmitter pad and the receiver pad are horizontally aligned based on the received information.

203 220 210 In this case, the stopperinstalled in the parking area is not for determining the parking location of the electric vehicle, but plays a role to limit the electric vehicle so that the electric vehicle does not fall outside a parking range. The reason for this is that the size of an electric vehicle, the location at which the receiver padis attached within an electric vehicle, and the location of the transmitter padinstalled within a parking area have not been standardized.

240 210 220 222 210 222 The electric vehicleaccording to an embodiment of the present disclosure basically performs horizontal alignment by calculating the relative location of the transmitter padto the receiver padin real time as described above, but may correct a horizontal alignment error while finely moving the location of the electric vehicle in a direction in which the output of the receiver coilis maximized by applying a predetermined current to the transmitter padand sensing the output of the receiver coilfor more precise horizontal alignment during an alignment process.

8 FIG. is a diagram for describing a construction and operation method for horizontal alignment at a home parking lot in the wireless charging system according to another embodiment of the present disclosure.

8 FIG. 310 320 200 200 220 210 310 320 Referring to, in the horizontal alignment method according to another embodiment of the present disclosure, wheel guidesand stoppersthat hold the stop location of the electric vehicle upon parking are additionally installed on both sides of the parking areain the entrance direction of the electric vehicle in the parking area. Horizontal alignment between the receiver padand the transmitter padmay be automatically performed upon parking by using the wheel guidesand the stoppers.

240 310 240 320 220 240 210 210 220 More specifically, when the electric vehicleis parked, the wheels of the electric vehicle enter a predetermined location by the wheel guides. When the electric vehicleis parked so that the stopperscome into contact with the wheels, the receiver padof the electric vehicleand the transmitter padmay be horizontally aligned. Such a method has an advantage in that horizontal alignment can be simply performed even without a complex process compared to the horizontal alignment method. However, such a case may be applied to a case in which the location of the transmitter padhas been previously set within a parking area by considering the size of a specific electric vehicle and the location at which the receiver padis attached.

210 220 8 FIG. Accordingly, the horizontal alignment method according to another embodiment of the present disclosure may be preferably applied for charging convenience of a specific electric vehicle when parking is performed for a personalized parking space, such as home. In this case, it is preferred that an electric vehicle performs head-on parking. A vertical alignment method and an FOD method between the transmitter padand the receiver pad, which are described hereinafter, may also be identically applied to the case of the wireless charging system for an electric vehicle illustrated in.

210 220 In an embodiment of the present disclosure, the wireless charging system for an electric vehicle can maximize power transmission efficiency by additionally performing vertical alignment between the transmitter padand the receiver padwhen horizontal alignment is completed.

9 FIG. 210 212 210 212 220 212 212 212 Referring to, the transmitter padaccording to an embodiment of the present disclosure includes the transmitter coilcapable of a vertical movement on the transmitter pad. Accordingly, vertical alignment can be performed so that the transmitter coiland the receiver padhave a predetermined air gap by adjusting the height of the transmitter coil. The height of the transmitter coil may be fixed to a preset air gap, but the height of the transmitter coilmay be adjusted in real time so that charging efficiency is maximized depending on surrounding environment conditions, such as a voltage or temperature of a battery. To this end, the wireless charging system for an electric vehicle according to an embodiment of the present disclosure may previously collect and store information on an optimal height of the transmitter coilaccording to at least one surrounding environment factor.

212 220 In this case, in an embodiment of the present disclosure, a distance between the transmitter coiland the receiver padmay be controlled within a predetermined size (e.g., 20 mm) in order to prevent the inflow of an external metallic foreign substance during charging and to maintain the influence of a magnetic field on an external creature within a reference value or less.

230 222 222 Furthermore, as in the fine horizontal alignment, the wireless charging platform may operate to drive the inverterso that the inverter applies a predetermined current to the transmitter coil when vertical alignment is started and to perform fine vertical alignment up to a point at which the output of the receiver coilis maximized by sensing the output of the receiver coil.

230 210 212 230 212 220 Furthermore, it is preferred that vertical alignment is performed so that a soft switching condition for the inverteris satisfied in a way that the transmitter padperforms tuning while gradually raising the height of the transmitter coil from an original location of the transmitter coil during a process of adjusting the height of the transmitter coil. For example, in order to satisfy the soft switching condition for the inverter, the tuning needs to be performed in a way that leakage inductance is reduced. That is, the soft switching is guaranteed only when a resonant frequency on the transmission (TX) side is placed at a lower location than a switching frequency. When the air gap is increased, the leakage inductance is increased, and the resonant frequency is formed on the lower side. When the air gap is slightly reduced, the leakage inductance is gradually reduced, and the resonant frequency is gradually increased. When the resonant frequency reaches a predetermined range in which the resonant frequency is lower than the switching frequency, the tuning is stopped. In this case, a rectifier that rectifies the output of the receiver coil may be provided. A phase difference between the voltage and current of the rectifier may be detected. Fine vertical alignment between the transmitter coiland the receiver padmay be performed based on the phase difference.

212 222 210 The wireless charging system for an electric vehicle starts charging when the vertical alignment of the transmitter coilwith the receiver coilis completed. When the air gap between the transmitter coil and the receiver coil is changed by a predetermined value or more because the height of the electric vehicle is changed due to a reason, such as that a person gets out of the electric vehicle or gets on the electric vehicle, during charging, the wireless charging system may temporarily stop the charging and then start the charging after adjusting the height of the transmitter padagain.

10 FIG. 9 FIG. is a diagram that exemplifies the structure of the transmitter pad for the vertical alignment illustrated in.

210 In an embodiment of the present disclosure, the transmitter padmay be implemented to include the transmitter coil thereon, a structure capable of adjusting the height of the transmitter coil, and a self-driving unit for driving the structure so that the height of the transmitter pad is autonomously adjusted.

10 FIG. 400 210 410 212 210 410 430 410 420 Referring to, the height adjustment deviceof the transmitter padaccording to an embodiment of the present disclosure includes an X-liftincluding two X-shaped structures disposed between the bottom plate and transmitter coilof the transmitter pad. Four upper, lower, left, and right structures on one side of the X-liftmay be implemented with fixed bearings. Four upper, lower, left, and right structures on the other side of the X-liftmay be implemented with sliding bearings.

410 440 420 440 400 450 440 450 440 410 420 212 450 440 212 Furthermore, the X-liftincludes a connection barthat connects structures connected to two of the four sliding bearings, and may be constructed to be driven by pushing or pulling the connection bar. To this end, the height adjustment devicemay include a rectilinear driving unitthat pushes or pulls the connection bar. For example, when the rectilinear driving unitpushes the connection bar, the structures of the X-liftconnected to the sliding bearingsare slid to lower the height of the transmitter coil. When the rectilinear driving unitpulls the connection bar, the height of the transmitter coilis raised.

450 440 440 210 450 460 440 460 210 400 462 460 464 212 460 In this case, the rectilinear driving unitthat drives the connection baris connected between the connection barand the bottom plate of the transmitter pad, and may be constructed by using a bolt-nut method or a rack-pinion structure. For example, the rack-pinion rectilinear driving unitmay fix one side of a rack gearto the connection bar, and the other side of the rack gearmay be configured to perform a rectilinear motion through linear bearings provided at the bottom of the transmitter pad. Furthermore, the height adjustment devicemay include a deceleration gear having a predetermined gear ratio with respect to a pinion gearcorresponding to the rack gearand a motor, and may be implemented to adjust the height of the transmitter coilby pushing or pulling the rack gear.

410 222 212 212 In an embodiment of the present disclosure, the X-liftmay further include fixing means for fixing the structure so that the structure is not moved after alignment with the receiver coilis completed by adjusting the height of the transmitter coil. The fixing means may be implemented to be manually or automatically released depending on situations so that the transmitter coilfalls to an original point location.

450 470 460 440 480 460 460 440 470 480 490 470 470 490 470 460 212 For example, the rack-pinion rectilinear driving unitmay include a ringconfigured to be pressed by a spring when the rack gearis connected to the connection bar. A grooveis formed in the rack gear. The rack gearmay be configured so that the connection barperforms a rectilinear motion when the ringis engaged with the groove. Furthermore, an electromagnetis provided on the ring. In case of emergency, the ringis raised by operating the electromagnet. Accordingly, the ringand the rack gearmay be separated from each other, and the transmitter coilnaturally falls by gravity and returns to its original location.

410 212 Such a construction provides an additional effect that prevents damage to the X-liftwhen the transmitter coilis excessively pressed by an external force.

460 462 462 212 410 462 According to another embodiment, the threads of the rack gearand the pinion gearmay be formed to have a gentle slope. The pinion gearmay be configured to have a state in which the pinion gear has been pressed by the spring without being fixed. Accordingly, when predetermined pressure or more is applied from the top of the transmitter coil, the X-liftmay be implemented to automatically fall as the pinion gearis lifted and slipped.

440 210 210 212 440 Although not illustrated in the drawings, the rectilinear driving unit may include a bolt and a nut. In this case, one end of the bolt is fixed to the connection bar, but is connected thereto so that the bolt can be freely rotated. The other end of the bolt may be fixed to the bottom plate of the transmitter padby the nut fastened to the bolt. Furthermore, a gear is formed in the bolt, and a deceleration gear having a predetermined gear ratio corresponding to the gear and a motor are provided in the bottom plate of the transmitter pad. Accordingly, the height of the transmitter coilmay be implemented to be adjusted by pushing or pulling the connection baras the motor rotates the bolt.

Like the rack-pinion rectilinear driving unit, the bolt-nut rectilinear driving unit may further include fixing means based on the ring-groove structure. Likewise, the ring-groove structure may be configured to be released through the electromagnet.

240 210 210 212 210 212 210 210 2 FIG. In the rectilinear driving unit, interference may occur in the electric vehicleupon parking because the entire height of the transmitter padis excessively raised at the basic height of the transmitter pad, that is, even when the transmitter coilfalls and is placed at the original location, depending on the arrangement of the motor-decelerator assembly or other instrument. In such a case, the entire height of the transmitter padmay be lowered by stretching the motor-decelerator assembly to the outside of the transmitter coiland extending the rack gear. In this case, the transmitter padis further extended in a direction on one side thereof. Accordingly, the transmitter padmay be implemented in a form in which a total size of the transmitter pad has an increased area as illustrated in.

11 FIG. is a diagram for describing a vertical alignment method for the transmitter coil using a pad aligner according to another embodiment of the present disclosure.

210 500 212 222 212 500 212 In another embodiment of the present disclosure, the transmitter padincludes a movable pad alignerthat adjusts the height of the transmitter coilon the outside. When a charging request is received from a specific electric vehicle, vertical alignment may be performed so that the air gap between the receiver coiland the transmitter coilis constantly maintained by invoking the movable pad alignerand adjusting the height of the transmitter coil.

212 222 210 210 500 210 That is, in the vertical alignment method according to another embodiment of the present disclosure, direct driving means for vertical alignment between the transmitter coiland the receiver coilis disposed outside the transmitter padnot within the transmitter pad. Multiple (e.g., 20 to 50) wireless chargers can be aligned by using one pad aligner. Accordingly, there are advantages in that the size of the transmitter padcan be minimized, a structure can be simplified, system efficiency can be improved, and a manufacturing cost price can be reduced.

11 FIG. 500 522 510 520 521 520 530 520 521 540 542 543 544 545 500 540 545 210 220 540 545 To this end, referring to, the pad alignermay basically include a traveling driving unitcapable of a direction change, a body, two arms, one or more forksprovided inside each arm, an elevation driving unitthat raises the armor the fork, one or more cameras, a lidar sensor, lighting devicesand, a thermal imaging camera, and a pad aligner controller (not illustrated) including wireless communication. The pad aligneraccording to an embodiment of the present disclosure includes the camerasand the thermal imaging camera, and can inspect whether a foreign substance is present on the transmitter pador the receiver padeven without using a separate expensive FOD device by using the camerasand the thermal imaging camera. This is described in detail during the course of describing an FOD method according to an embodiment of the present disclosure.

500 542 540 210 543 544 540 222 521 210 212 In an embodiment of the present disclosure, the pad alignermoves to a parking area in which an electric vehicle that requires charging is disposed in an autonomous manner by using the lidar sensorand the cameras, approaches the transmitter padthrough the lighting devicesandand the cameras, and then may perform vertical alignment on the receiver coilby deploying the forkto both sides of the transmitter padand moving the transmitter coil.

500 212 Furthermore, the pad alignermay be designed to facilitate work that raises and moves the transmitter coil.

500 222 212 500 510 520 212 521 520 521 521 212 512 212 In this case, the pad alignermay also be configured to easily perform vertical alignment on the receiver coilby raising and moving the transmitter coil. For example, the pad alignerprotrudes by being integrally fixed to the bodyso that the two armscan easily raise and move the transmitter coil. The forkprovided inside each armmay have a function for stretching and pulling out the forkso that the forkcan hold the transmitter coil. Furthermore, the forkmay be implemented to rise and fall in the vertical direction in order to adjust the location of the transmitter coil.

11 FIG. 210 500 212 212 521 210 500 212 521 Accordingly, referring to, after approaching the transmitter pad, the pad alignerholds and raises the transmitter coil, more specifically, a plate that constitutes the transmitter coil, by deploying the forktoward the transmitter pad. Thereafter, the pad alignerperforms vertical alignment by vertically moving the transmitter coil, and then performs a series of vertical alignment processes of returning the forkto its original location.

210 550 521 500 212 The transmitter padmay include two or more grooves or protrusionson the side thereof so that the forkof the pad alignercan raise the transmitter coil.

210 212 222 212 500 Furthermore, although not clearly illustrated in the drawings, the transmitter padmay be implemented to have a structure capable of vertically moving the transmitter coil. Fixing means that fixes the structure after alignment with the receiver coilis completed by moving the transmitter coilby the pad alignermay be further provided.

12 13 FIGS.and are diagrams for describing an FOD method according to an embodiment of the present disclosure.

210 210 210 As described above, the wireless charging system for an electric vehicle according to an embodiment of the present disclosure is implemented to inspect whether a foreign substance is present on the transmitter pador the receiver pad even without a separate complex and expensive FOD device. Furthermore, the size of the transmitter padcan be reduced, system efficiency can be improved, and a manufacturing cost for the entire wireless charging system can be reduced because functions, such as the FOD function, are separately implemented outside the transmitter pad.

210 230 To this end, the wireless charging system for an electric vehicle according to an embodiment of the present disclosure can inspect whether a foreign substance has been attached on the transmitter pador below the receiver pad prior to or during the charging of an electric vehicle by using the structure of the inverterdisposed in a parking area.

12 FIG. 230 234 236 210 230 230 234 236 210 234 230 210 234 First, referring to, in an embodiment of the present disclosure, the inverteris installed outside the parking area, and includes the cameraand a lighting devicedirected toward the transmitter pad. Accordingly, the invertermay perform FOD inspection prior to the start of charging. More specifically, the invertermay be installed so that the cameraand the lighting devicehave a predetermined height or more from the floor of the parking area in order for the top of the transmitter padto be well monitored by the camera. Through such a construction, the invertermay be implemented to inspect and determine whether a metallic foreign substance is present on the transmitter padin a visual way by using the camerawhen an electric vehicle is not present in the parking area.

230 The invertermay perform analysis by using big data related to a shape or color of a metallic foreign substance in performing metallic FOD. Furthermore, the accuracy of FOD can be gradually improved because the inverter continuously learns result data during such an analysis process.

230 238 210 230 238 210 238 230 210 238 212 230 212 According to another embodiment, the inverteris installed outside the parking area, and may perform FOD inspection by using the thermal imaging cameradirected toward the transmitter pad. More specifically, the inverteris installed so that the thermal imaging camerahas a predetermined height or more from the floor surface of the parking area in order for the top of the transmitter padto be easily monitored by the thermal imaging camera. When an electric vehicle is not present in the parking area, the invertermay inspect whether a heating point attributable to a metallic foreign substance is present on the transmitter padthrough the thermal imaging cameraby periodically applying a current to the transmitter coil. In this case, the invertermay be configured to separately analyze heating attributable to a metallic foreign substance and the heating of the transmitter coilitself.

210 230 240 230 240 240 230 240 When determining that a foreign substance is present on the transmitter pad, the invertermay transmit a warning message, reading that a driver who approaches for charging should remove the foreign substance prior to parking, to the electric vehicle. When the driver removes the foreign substance, the inverterperforms FOD inspection again, and notifies the electric vehicleof the state in which the electric vehicle can be charged. Thereafter, when the electric vehicleis parked in the parking area, the invertermay control the electric vehicleso that charging can be started.

13 FIG. 13 FIG. 210 600 610 212 212 210 220 610 230 Furthermore, referring to, the transmitter padaccording to an embodiment of the present disclosure includes one or more second thermal imaging camerasor second camerasthat protrude from the top of the transmitter coilwithin a predetermined distance or less (e.g., within 10 mm) outside the transmitter coil, and may inspect whether a heating point attributable to a metallic foreign substance or an external creature is present between the transmitter padand the receiver padduring the charging of an electric vehicle in real time inspect. Although not illustrated in, the second cameramay include a lighting device like the camera of the inverter.

600 610 212 212 13 FIG. In this case, it is preferred that the second thermal imaging camerasand the second camerasprovided along with the transmitter coilare configured to observe a space between the transmitter pad and the receiver pad without a blind spot. To this end, as illustrated in, the cameras are formed to gather at an outside central part of the transmitter coiland to protrude therefrom, and may be implemented with wide-angle cameras capable of securing a wide viewing angle.

210 212 210 210 600 610 13 FIG. In the embodiment of the present disclosure, a method of reducing the entire height of the transmitter padby disposing a driving unit for vertical alignment, for example, the motor-decelerator assembly outside the transmitter coiland extending the rack gear has been proposed as a method of reducing the entire height of the transmitter pad. In the case of such a construction, a clearance is formed because the transmitter padis lengthened in a direction on one side thereof. In an embodiment of the present disclosure, preferably, as illustrated in, the second thermal imaging camerasand the second camerasmay be installed by using the clearance.

According to such an installation method, there is an effect in that a space between the transmitter pad and the receiver pad can be more accurately observed even in the situation in which a distance between the transmitter pad and the receiver pad is variously changed upon vertical alignment because the size of each electric vehicle or the location at which the receiver pad is installed is different.

230 212 220 212 220 According to another embodiment, the inverterincludes a third thermal imaging camera or a third camera and a third lighting device at the height where the air gap between the transmitter coiland the receiver padcan be observed, and may be implemented to inspect whether a heating point attributable to a metallic foreign substance is present between the transmitter coiland the receiver pador whether an external creature is sensed nearby during charging.

12 13 FIGS.and 210 The wireless charging system for an electric vehicle according to an embodiment of the present disclosure includes at least one or more pieces of means, among the camera or the thermal imaging camera illustrated in, and may inspect whether a metallic foreign substance is present on the transmitter pad. Furthermore, the wireless charging system may also implement the LOD function in addition to the FOD function by using the means.

500 500 11 FIG. The wireless charging system for an electric vehicle according to an embodiment of the present disclosure may be configured to inspect whether a metallic foreign substance is present through the pad alignerwhen alignment is performed by using the pad aligneras illustrated in.

500 210 220 540 543 544 For example, the pad alignermay inspect whether a foreign substance is attached on the transmitter pador below the receiver padby using the cameraand the lighting devicesandincluded in the pad aligner.

210 545 230 Furthermore, the pad aligner may determine whether a metallic foreign substance is present by detecting a heating point on the transmitter padthrough the thermal imaging camerawhen the inverterapplies a current to the transmitter coil.

14 FIG. is a diagram for describing a structure and charging process for the wireless charging system for an electric vehicle according to an embodiment of the present disclosure.

210 230 The wireless charging system for an electric vehicle according to an embodiment of the present disclosure includes one or more wireless charging parking areas in each of which the transmitter padand the inverterare installed. Such wireless charging parking areas gather to form a wireless charging parking zone. In this case, a procedure in which an electric vehicle that requires wireless charging enters the wireless charging parking zone and performs charging is as follows.

230 210 234 238 230 While an electric vehicle is not parked in the wireless charging parking area, the inverterinspects whether a metallic foreign substance is present on the transmitter padby using the cameraand the thermal imaging cameraembedded in the inverter.

When a specific electric vehicle enters the wireless charging parking zone for wireless charging, the electric vehicle is parked by selecting a parking area in which a foreign substance on the transmitter pad is not detected, among empty parking areas, or is parked after a foreign substance is removed when the foreign substance on the transmitter pad is detected.

230 240 230 240 700 230 240 240 700 230 The invertercorresponding to a corresponding parking area recognizes the number of a corresponding electric vehicle, and starts communication through pairing with a unique communication ID that is previously assigned in accordance with the number of the electric vehicle. The inverteridentifies the charging intention of the electric vehicle, and performs a charging process when identifying the charging intention. To this end, a wireless charging platformperforms communication between a smartphone of a user who requests charging and the inverter. Thereafter, when receiving a charging request from the electric vehicleor the smartphone of the user who owns the electric vehicle, the wireless charging platformshares the charging request with the inverterthrough communication and performs a charging procedure.

240 210 230 230 The electric vehiclerecognizes front and side parking lines by using the parking line recognition function and also collects information on a relative location of the transmitter padto the inverterthrough communication with the inverter.

240 210 220 210 220 210 230 The electric vehiclerecognizes the horizontal alignment state between the transmitter padand the receiver padby calculating the relative location of the transmitter padto the receiver padin real time based on the recognition information of the front and side parking lines and information on the location of the transmitter padthat is collected from the inverter.

240 220 300 210 The electric vehicledisplays the receiver padat the center of the monitorwithin the electric vehicle, and displays the relative location of the transmitter padin the parking area on a screen in accordance with the display of the receiver pad.

240 300 240 220 210 The driver manually parks the electric vehiclewith reference to the monitoror automatically parks the electric vehicleby using the automatic parking function so that the receiver padof the electric vehicle is horizontally aligned with the transmitter padof the parking area.

230 212 240 222 Thereafter, the inverterapplies a predetermined current to the transmitter coil. The electric vehicleis finely aligned in the X-Y axis by searching for a point at which the output of the receiver coilis maximized.

220 210 When the horizontal alignment is completed, the wireless charging system for an electric vehicle additionally performs vertical alignment between the receiver padand the transmitter pad.

210 212 220 212 In this case, the transmitter padincludes the transmitter coilcapable of a vertical movement thereon. Accordingly, the vertical alignment with the receiver padcan be performed by adjusting the height of the transmitter coil.

210 500 212 222 212 500 212 In another embodiment, the transmitter padincludes the movable pad alignerthat adjusts the height of the transmitter coiloutside the transmitter pad. When receiving a charging request from a specific electric vehicle, the wireless charging system for an electric vehicle may perform vertical alignment so that the air gap between the receiver coiland the transmitter coilis constantly maintained by invoking the movable pad alignerand adjusting the height of the transmitter coil.

210 222 230 212 212 222 Likewise, precise vertical alignment may be performed in a way that the transmitter padsenses the output of the receiver coilaccording to a predetermined current that is applied from the inverterto the transmitter coilupon vertical alignment and the height of the transmitter coilis finely adjusted in a direction in which the output of the receiver coilis maximized based on the results of the sensing.

222 230 240 210 220 230 When both the horizontal alignment and the vertical alignment with the receiver coilare completed, the inverterstarts charging through communication with the electric vehicle. When an environmental change, such as a temperature or humidity, occurs during the charging or when an air gap between the transmitter padand the receiver padis changed by a predetermined value or more because the height of the electric vehicle is changed due to a factor, such as that a user gets on or out of the electric vehicle, the invertertemporarily stops the charging and performs an alignment process again.

210 230 210 500 240 210 230 It is possible to inspect whether a metallic foreign substance is present on the transmitter padwhether a creature is present nearby by using the thermal imaging camera and the camera included in the inverter, the transmitter pad, or the pad alignereven in the state in which the electric vehicleis being charged. In this case, when a metallic foreign substance is present on the transmitter pador a creature is sensed nearby, the inverterimmediately stops the charging.

230 240 When the charging is completed, the inverterchecks the billing function of the electric vehicleand then performs a fee settlement procedure.

14 FIG. 14 FIG. 14 FIG. The processes inhave been described as being sequentially executed, but the present disclosure is not essentially limited thereto. In other words, the processes described with reference tomay be changed and executed or one or more of the processes may be executed in parallel. Accordingly,is not limited to the time-series sequence.

The embodiments of the disclosure have been disclosed in this specification and drawings. Although specific terms have been used in this specification and drawings, they are merely used in common meanings in order to easily describe the technical contents of the disclosure and are not intended to limit the scope of the disclosure. It is evident to a person having ordinary knowledge in the art to which the disclosure pertains that in addition to the disclosed embodiments, other modified examples based on the technical spirit of the disclosure may be practiced.

100 200 102 202 ,: parking area,: parking line 110 210 ,: transmitter pad 112 212 ,: transmitter coil 120 220 ,: receiver pad 122 222 ,: receiver coil 130 230 132 232 ,: inverter,: charging cable 203 320 234 ,: stopper: camera 236 238 : lighting device: thermal imaging camera 240 242 : electric vehicle: electric vehicle camera 300 310 : monitor: wheel guide 400 410 : height adjustment device: X-lift 420 430 : sliding bearing: fixed bearing 440 : connection bar 450 : rectilinear driving unit 460 462 : rack gear: pinion gear 464 470 : motor: ring 480 490 : groove: electromagnet 500 510 : pad aligner: aligner body 520 521 : arm: fork 522 530 : driving unit: elevation driving unit 540 542 : camera: lidar sensor 543 544 ,: lighting device 545 : thermal imaging camera 600 : second thermal imaging camera 610 : second camera 700 : wireless charging platform